target.def (class_likely_spilled_p): New hook.

	* target.def (class_likely_spilled_p): New hook.
	* doc/tm.texi.in (TARGET_CLASS_LIKELY_SPILLED_P): Document.
	* doc/tm.texi: Regenerate.
	* targhooks.c (default_class_likely_spilled_p): New function.
	* targhooks.h (default_class_likely_spilled_p): Declare.
	* regs.h (CLASS_LIKELY_SPILLED_P): Remove.
	* combine.c: (cant_combine_insn_p, likely_spilled_retval_p): Use
	TARGET_CLASS_LIKELY_SPILLED_P target hook. Use HARD_REGISTER_P macro.
	Use fixed_reg_set instead of fixed_regs.
	* cse.c (hash_rtx_cb): Use TARGET_CLASS_LIKELY_SPILLED_P target hook.
	* calls.c (avoid_likely_spilled_reg): Ditto.
	* ira-conflicts.c: (ira_build_conflicts): Ditto.
	* ira.c (update_equiv_regs): Ditto.
	* mode-switching.c (create_pre_exit): Ditto.
	* regmove.c (find_matches): Ditto.
	(regclass_compatible_p): Use TARGET_CLASS_LIKELY_SPILLED_P target
	hook.
	* reload.c (SMALL_REGISTER_CLASS_P): Remove macro.
	(small_register_class_p): New inline function.
	(push_secondary_reload, find_reusable_reload, find_reloads): Use
	small_register_class_p instead of SMALL_REGISTER_CLASS_P.

	* config/i386/i386.h (CLASS_LIKELY_SPILLED_P): Remove.
	* config/i386/i386.c (ix86_class_likely_spilled_p): New.
	(TARGET_CLASS_LIKELY_SPILLED_P): Define.

From-SVN: r163779

1 files changed, 18 insertions, 0 deletions

diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index f0bdf68..24f5c1b3 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -2858,6 +2858,24 @@ Do not define this macro if you do not define
 is @code{BITS_PER_WORD} bits wide is correct for your machine.
 @end defmac
 
+@hook TARGET_CLASS_LIKELY_SPILLED_P
+A target hook which returns @code{true} if pseudos that have been assigned
+to registers of class @var{rclass} would likely be spilled because
+registers of @var{rclass} are needed for spill registers.
+
+The default version of this target hook returns @code{true} if @var{rclass}
+has exactly one register and @code{false} otherwise.  On most machines, this
+default should be used.  Only use this target hook to some other expression
+if pseudos allocated by @file{local-alloc.c} end up in memory because their
+hard registers were needed for spill registers.  If this target hook returns
+@code{false} for those classes, those pseudos will only be allocated by
+@file{global.c}, which knows how to reallocate the pseudo to another
+register.  If there would not be another register available for reallocation,
+you should not change the implementation of this target hook since
+the only effect of such implementation would be to slow down register
+allocation.
+@end deftypefn
+
 @defmac CLASS_LIKELY_SPILLED_P (@var{class})
 A C expression whose value is nonzero if pseudos that have been assigned
 to registers of class @var{class} would likely be spilled because